A solar array for a satellite is generally constructed of a series of flat panels which are structurally connected to each other by hinges and to the satellite by a yoke which incorporates a deployment mechanism. The hinged connection allows the panels to be folded in a secure and compact position for launching of the satellite. Once the satellite obtains orbit, the panels are unfolded to deploy the solar array. Each panel supports hundreds of individual cells bonded to a face of the panel to receive light from the sun and convert it to power to drive the satellite systems.
The design of each panel is complex in that it must provide structural integrity to the array, while providing other functions such as electric insulation, thermal conductivity and heat dissipation for the individual cells. When the array is deployed, significant moments are generated with each motion of the satellite. Such motions will occur often, as the attitude and orbit of the satellite is adjusted during normal station keeping functions. The stresses experienced by the panels, therefore are considerable and varied as the array flexes over its extended span. In particular, in solar arrays which are deployed after separation from the rocket, but before final orbit is achieved, a design limiting bending stress occurs when the main thruster is fired at apogee to optimize the orbit.
Each array has a harmonic motion depending on it dimensions, density and components which must be damped to prevent damage to the array. In addition, one of the key design criteria for all components of a satellite is weight and this necessarily plays an important role in the construction of the panels.
U.S. Pat. No. 5,614,033, which issued to Robinson et al, describes a honeycomb panel which provides a combination of structural integrity and a core that is an effective heat sink. U.S. Pat. No. 5,520,747 shows an array structure which utilizes reflective panels to increase the efficiency of the solar cells and provide structure to the panel in deployment.
Honeycomb sandwich structures, consisting of flat high strength outer surface layers and a cellular honeycomb core, have proved effective building elements for solar array panels. A specific honeycomb structure is described in the '033 patent cited above.
It is the purpose of this invention to provide a weight reduction of as much as twenty percent while distributing the stresses more evenly over the solar panel array.